I am a retired Electronic
Design Engineer and are fully capable of designing a video camera into a model
railway truck but the market is so small that the cost of the components alone
in small quantities would be several hundreds of pounds making them out of reach
for most modellers.

So what is the solution? As
many people have suspected the trick is to use a video device which is mass
produced for another purpose which can be adapted for a model railway Camera
Truck (Camtruck). The devices examined were Spy Pens and Spy Key Fobs. The
suppliers of these devices mostly don't know what is in them and can't answer
technical questions so the only solution is to buy them and take them apart.
Most of the devices I purchased were of very poor quality both in picture
quality and construction. These were rejected. Those that had a good video
quality were taken apart which is difficult because they were never intended to
be taken apart. They are glued or cold welded and extracting the electronics
often destroyed the circuits. I soon learned to buy the spy devices in pairs so
if the 1st was damaged I could perform an autopsy to determine how to take the
2nd apart safely. Most of the electronic modules could not be modified to either
fit in a truck or rotate the camera to point in the required direction. Those
that passed all the suitability tests were purchased in larger numbers for
production.

This process of buying
and examining spy devices cost me over a £1000 and many frustrating months of
work.

But the design of these spy
devices constantly changes so what was once a suitable device soon became
useless! To overcome the problem of consistent quality I communicated directly
with the manufactures who were all in China. This was difficult on two levels,
one the language (I don't speak Chinese) and second most were not interested in
such small quantities. Eventually I found a suppler who could not only speak and
write English but was prepared to make small modifications to my requirements
and very importantly, supplying them as an unmounted module. This worked for a
while by adding my relatively small quantities on to the larger batches he was
making for other Chinese manufactures of Spy devices. Modern electronic assembly
uses a process of robotic placement that is only economic in large quantities of
thousands or tens of thousands.

But then the Chinese
economy went into decline and his customers weren't buying so he could not add
my small quantities onto larger batches. My quantities are small. I have only
sold 312 Camtrucks in four years and I don't think the market will ever be in
the thousands!

I hope this has explained
why the supply of Camtrucks is so spasmodic. Also the price! They are hand made
and take many hours each to construct and test.